We will continue to investigate, at both cellular and molecular levels, the mechanisms by which adeno-associated satellite viruses (AAV) interfere with the replication and potential oncogenesis of their helper adenoviruses and herpesviruses. We will use conditionally defective helper viruses, namely temperature-sensitive mutants of human adenovirus type 31 and herpes simplex virus, known to be defective in viral DNA synthesis and/or other virus-specific functions. Complementation studies with these mutants will simplify dissection of the defective satellite replication cycle. Satellite viruses are defective at both the replication and maturation steps. We will analyze the products synthesized in these systems by the techniques of radioisotope labeling of viral DNA, ultracentrifugal analysis, electron microscopy and column chromatography and correlate these parameters with biological activity. We will extend the scope of these investigations through the use of host cells conditionally non-permissive for human adenoviruses. We will isolate AAV intracellular DNP complexes, to determine their role in the replication and segregation of single-stranded progeny DNA and in the production of mature virions. These studies should be of considerable importance in understanding the mechanisms controlling abrogation of adenovirus- and herpesvirus-derived tumors by adeno-associated satellite viruses.